Methods for quantitating water using ionic liquid salts

ABSTRACT

This disclosure provides methods and devices for quantitating, separating and/or detecting water in a liquid, gas or solid sample comprising one or more chemicals, the method comprising: providing the liquid, gas or solid sample comprising water and the one or more chemicals; and exposing said liquid, gas or solid sample to at least one solid support including at least one dicationic and/or tricationic species of Formula I or II adsorbed, absorbed or immobilized on the solid support.

CROSS REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. provisional application Ser.No. 61/538,640 filed Sep. 23, 2011. The disclosure of the application ishereby incorporated by reference.

FIELD

The present disclosure relates to methods for separating, detectingand/or quantitating water in a sample and devices therefor. Morespecifically, the disclosure relates to methods for separating,detecting or quantitating water in various materials using a polyionicliquid salt and devices for water quantitation comprising a polyionicliquid salt.

BACKGROUND

Versatile, rapid and accurate analytical techniques for the detectionand quantification of water in a variety of materials remain animportant and ubiquitous analytical problem. Indeed water is one of themost prevalent impurities in many industrial and consumer products andprocesses. In other cases, water is an essential component, theconcentration of which must be known accurately and controlled.

The determination of water content in solvents and consumer products,including foods, pharmaceuticals, and industrial materials, is of greatimportance. Indeed analytical testing for the presence and concentrationof water is one of the most frequent, important and ubiquitousmeasurements made in modern industrial society. Thus a versatile, simpleand efficient analytical technique for the accurate quantification ofwater is imperative. The essentially universal presence of waterrequires accurate, facile and sensitive techniques to quantify it. Whilevarious techniques such as gravimetry, Karl Fisher titration (KFT), gaschromatography, near IR spectrophotometry, solvatochromic sensing, F-NMRspectroscopy, isotope ratio mass spectrometry (IRMS) and others havebeen reported in the literature, only a few methods are widely acceptedand used.

Currently, the most commonly used method for water analysis is the KFT,which was first reported in 1935. In this titrametric method, I₂ isreduced to HI in the presence of water. There are four components in theKarl Fischer reagent consisting of: iodine, sulfur dioxide, a suitablebase (RN) (originally pyridine was used, but now imidazole is morecommon); and a suitable solvent such as methanol, ethanol, diethyleneglycol monomethyl ether, etc.

The accepted mechanism of this two step reaction is:CH₃OH+SO₂+RN→[RNH]SO₃CH₃H₂O+[RNH]SO₃CH₃+I₂+2RN→[RNH]SO₄CH₃+2[RNH]I

The end point is determined potentiometrically. Two types of KFT methodsare used. They are the coulometric titration and the volumetrictitration. Coulometric titration is used to detect trace amounts ofwater, ranging from 10 μg to 99 μg (1 ppm—5%), and it requires about 5 gor more of sample. Volumetric titration is used to detect waterquantities higher than 1 mg (10 ppm—100%), and the amount of samplerequired varies from 0.1 mg to 500 mg. Therefore, prior knowledge of theapproximate amount of water present in the sample is required inchoosing the correct KFT method of analysis.

Although KFT is a well-established method, interference of sidereactions, reagent instability, sample insolubility and pH issuesprevent it from being accepted as a universal method. Variations on thebasic KFT methodologies have been developed in an attempt to overcomethese problems. However, many issues still remain, not the least ofwhich is that the reagents degrade with time and there is residual waterin all KFT reagents.

Another applied method for water detection is based on gaschromatography (GC). Early attempts using GC were mainly based on packed(molecular sieve) columns, involving both direct detection by thermalconductivity detector (TCD) and indirect detection (i.e. reacting waterwith calcium carbide to convert to acetylene) with a flame ionizationdetector (FID). Peak asymmetry, poor sensitivity, poor efficiency,strong adsorption of water and many solvents by the stationary phase,overlapping of the water peak by other larger peaks, and the inabilityto detect higher amounts of water limited its application in many cases.Attempts to eliminate peak asymmetry, using wide-diameter open tubularcolumns and capillary columns showed some improvement. Additionally,most conventional capillary column GC stationary phases are degraded bywater.

One truly useful, broadly effective capillary GC method for water shouldmeet several criteria including the following: 1) Water should not alteror degrade the stationary phase, thereby altering retention times andpeak shapes; 2) There must be a considerable difference in the retentionof water and most/all organic solvents especially when the solvent peakis very large relative to the water peak; 3) The water peaks should showgood efficiency and symmetry; and 4) The water and solvent chromatogramshould have sufficient separation space for an appropriate, baselineseparated internal standard.

U.S. Pat. No. 8,182,581 to Armstrong et al reports diionic liquid saltscomprising a dicationic or dianionic molecules and a counter-ion, and amethod of using such diionic salts for separating one chemical from amixture of chemicals. The methods comprise steps of providing a mixtureof at least one first and at least one second chemical, and exposingthat mixture to at least one solid support including a diionic liquidsalt.

U.S. Pat. No. 8,097,721 to Armstrong et al describes triionic liquidslats comprising a tricationic or trianionic molecules and acounter-ion, and a method of using such triionic salts for separatingone chemical from a mixture of chemicals. The methods comprise steps ofproviding a mixture of at least one first and at least one secondchemical, and exposing that mixture to at least one solid supportincluding a triionic liquid salt.

SUMMARY

This disclosure provides methods for separating, detecting orquantitating water in a liquid, gas or solid sample. In an embodiment,there is provided a method for detecting or quantitating water in asample comprising: applying a sample to a capillary column having a gaschromatography stationary phase comprising at least one dicationicspecies of Formula I:

and a counter-ion, wherein each R is independently selected from thegroup consisting of alkyl, alkoxy, carbocyclyl, carbocyclylalkyl,heterocyclyl, heterocyclylalkyl and hydroxyalkyl; each m isindependently 0, 1, 2, 3 or 4; and s is 1, 2, 3, 4, 5 or 6; andseparating water from the sample to detect or quantitate water in thesample.

In another embodiment, there is provided a method for detecting orquantitating water in a sample comprising: applying a sample to acapillary column having a gas chromatography stationary phase comprisingat least one tricationic species of Formula II:Gc(A)₃  Formula IIand a counter-ion, wherein Gc is phenyl, cycloalkyl, Si, C, N or P,wherein each A is independently selected from the group consisting of:

wherein each of R₁, R₂, R₃ and R_(m) is independently selected fromalkyl, alkoxy, carbocyclyl, carbocyclylalkyl, heterocyclyl,heterocyclylalkyl and hydroxyalkyl; and separating water from the sampleto detect or quantitate water in the sample.

In yet another embodiment, there is provided a gas chromatography methodfor detecting or quantitating a component in a sample, comprising:applying a sample to a capillary column having a gas chromatographystationary phase comprising a dicationic species of Formula I or atricationic species of Formula II and a counter-ion, wherein Formulae Iand II are as defined above; separating a component from the sample; andquantitating the component by using a thermal conductivity detector.

In yet another embodiment, there is provided a device for separating,detecting or quantitating water, the device comprising a solid supportand at least one polyionic salt comprising a dicationic species ofFormula I or a tricationic species of Formula II and a counter-ion,wherein the polyionic salt is adsorbed, absorbed or immobilized on thesolid support, wherein Formulae I and II are as defined above.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates ionic liquid gas chromatography stationary phasesused in Example 1.

FIG. 2 is a series of chromatograms illustrating the relative retentionorders of water and different organic solvents.

FIG. 3 is an example of improved resolution and peak symmetry using oneof ionic liquid based stationary phase (A), (B) and (C), and acommercial PEG column (D).

FIG. 4 is a plot of normalized response versus amount of spiked waterinjected onto HAIM-PEF column (50-200 mL volumes of water were spikedinto 1 ml of SRM 8509 using 0.5 μl calibrated Hamilton syringe).

FIG. 5 is an illustration showing the number of successful waterseparations on each of the three IL based columns.

FIG. 6 is an example of the separation of organic solvents in waterusing ionic liquid based stationary phase.

FIG. 7 is a table of exemplary dicationic species.

FIG. 8 is a table of exemplary tricationic species.

DETAILED DESCRIPTION

One exemplary embodiment described herein is an effective and sensitiveionic liquid (IL) based capillary gas chromatographic (GC) method with athermal conductivity detector (TCD) for the determination of watercontent in samples. The open tubular capillary columns, coated withspecific ILs developed in the example below, tremendously increased thesensitivity and ruggedness of this technique. The absolute water contentin 50 different solvent samples was determined by using either acetoneor acetonitrile as an internal standard. The lower detection limit ofthis example is about 2 ng water. Samples containing higher levels ofwater are also readily analyzed without pretreatment. In anotherexemplar embodiment, organic solvents can be measured in water by thesame approach using either TCD or a flame ionization detector (FID). Acomparison between IL based columns and commercial columns revealed theenhanced performance of the IL based columns. Standardization wascarried out with National Institute of Standards and Technology (NIST)reference materials and the accuracy was compared with anotherindependent method (Karl-Fischer titration). The developed method ishighly sensitive, fast, and is not affected by interferences and sidereactions common with existing Karl-Fischer-titration (KFT) methods.This exemplar approach can greatly simplify the analysis of water in avariety of applications. The approach can also be applied to gaseous andsolid samples.

A. DEFINITIONS

The term “alkenyl” refers to a straight or branched hydrocarbyl groupwith at least one site of unsaturation, i.e. a carbon-carbon, sp2 doublebond. In an embodiment, alkenyl has from 2 to 15 carbon atoms. In someembodiments, alkenyl is a C₂-C₁₀ alkenyl group or a C₂-C₆ alkenyl group.Examples of alkenyl groups include, but are not limited to, ethylene orvinyl (—CH═CH₂), allyl (—CH₂CH═CH₂), cyclopentenyl (—C₅H₇), and5-hexenyl (—CH₂CH₂CH₂CH₂CH═CH₂).

The term “alkoxy” refers to an alkylether, i.e., —OR, wherein R is alkylas defined herein. Non-limiting examples of alkoxy include methoxy(—OCH₃), ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy,tert-butoxy, and the like.

The term “alkyl” refers to an alkane-derived radical containing from 1to 20 carbon atoms. Alkyl includes straight chain alkyl, branched alkyland cycloalkyl. Straight chain or branched alkyl groups contain from1-15 carbon atoms, such as methyl, ethyl, propyl, isopropyl, butyl,t-butyl, and the like. Alkyl also includes straight chain or branchedalkyl groups that contain or are interrupted by one or more cycloalkylportions. Examples of this include, but are not limited to,4-(isopropyl)-cyclohexylethyl or 2-methylcyclopropylpentyl. The alkylgroup is attached at any available point to produce a stable compound.The term alkyl is also meant to encompass a fully substituted carbon.

The term “alkylene” refers to a divalent alkane-derived radicalcontaining 1 to 20 carbon atoms, such as 1 to 15 carbon atoms, 3 to 20carbon atoms, 3 to 12 carbon atoms, or 3 to 9 carbon atoms, from whichtwo hydrogen atoms are taken from the same carbon atom or from differentcarbon atoms. Examples of alkylene include, but are not limited to,methylene —CH₂—, ethylene —CH₂CH₂—, and the like.

The term “alkynyl” refers to a straight or branched carbon-chain groupwith at least one site of unsaturation, i.e., a carbon-carbon, sp triplebond. In an embodiment, alkynyl is a C₂-C₁₋₅ alkynyl group, a C₂-C₁₀alkynyl group or a C₂-C₆ alkynyl group. Non-limiting examples of alkynylgroups include acetylenic (—C≡CH) and propargyl (—CH₂C≡CH).

The term “amino” refers to —NH₂. The term “amino” is meant to encompassa “monosubstituted amino” wherein one of the hydrogen radicals isreplaced by a non-hydrogen substituent; and a “disubstituted amino”wherein both of the hydrogen atoms are replaced by non-hydrogensubstituents, which may be identical or different.

The term “ammonium” refers to a positively charged polyatomic cation ofthe chemical formula

wherein the R groups are individually H or an organic radical group.Ammonium also embraces positively charged or protonated substitutedamines (such as protonated tertiary amine). An “optionally substitutedammonium” is an ammonium wherein the organic radical group, R, isoptionally substituted with other organic radical groups.

The term “carbocyclyl” means a saturated cyclic (i.e., “cycloalkyl”),partially saturated cyclic (i.e., “cycloalkenyl”), or completelyunsaturated (i.e., “aryl”) hydrocarbyl substituent containing from 3 to14 carbon ring atoms (“ring atoms” are the atoms bound together to formthe ring or rings of a cyclic substituent). A carbocyclyl may be asingle ring (monocyclic) or polycyclic ring structure.

A carbocyclyl may be a single ring structure, which typically containsfrom 3 to 7 ring atoms, more typically from 3 to 6 ring atoms, and evenmore typically 5 to 6 ring atoms. Examples of such single-ringcarbocyclyls include cyclopropyl (cyclopropanyl), cyclobutyl(cyclobutanyl), cyclopentyl (cyclopentanyl), cyclopentenyl,cyclopentadienyl, cyclohexyl (cyclohexanyl), cyclohexenyl,cyclohexadienyl, and phenyl.

A carbocyclyl may alternatively be polycyclic or contain more than onering. Examples of polycyclic carbocyclyls include bridged, fused,spirocyclic, and isolated carbocyclyls. In a spirocyclic carbocyclyl,one atom is common to two different rings. An example of a spirocycliccarbocyclyl is spiropentanyl. In a bridged carbocyclyl, the rings shareat least two common non-adjacent atoms. Examples of bridged carbocyclylsinclude bicyclo[2.2.1]heptanyl, bicyclo[2.2.1]hept-2-enyl, andadamantanyl. In a fused-ring carbocyclyl system, multiple rings may befused together, such that two rings share one common bond. Examples oftwo- or three-fused ring carbocyclyls include naphthalenyl,tetrahydronaphthalenyl (tetralinyl), indenyl, indanyl (dihydroindenyl),anthracenyl, phenanthrenyl, and decalinyl. In an isolated carbocyclyl,the rings are separate and independent, as they do not share any commonatoms, but a linker exists between the rings.

The term “carbocyclyl” encompasses protonated carbocyclyl, such as

The term “carbocyclylalkyl” refers to the group —Z-carbocyclyl where Zis lower alkylene or substituted lower alkylene group.

The term “diionic salt” is used to describe a salt molecule, although,as the context suggests, it may be used synonymously with “diionicliquid” (“DIL”) and “diionic liquid salt” (“DILS”). A “diionic liquid”or “diionic liquid salt” in accordance with the present disclosure is aliquid comprised of diionic salts. Thus, sufficient diionic saltmolecules are present such that they exist in liquid form at thetemperatures indicated herein. This presumes that a single diionic saltmolecule is not a liquid. A diionic liquid is either (1) a dicationicliquid or (2) a dianionic liquid.

A “dicationic liquid salt” or “dicationic liquid”, as mentioned above,is either a salt molecule or a liquid comprised of dicationic salt(s),wherein the dicationic salt(s) is formed between a dicationic speciesand one or more counter-anions of equal and opposite charge. The term isnot meant to embrace a single species that has a +2 or −2 charge such asMg⁺² or SO₄ ⁻². Rather it contemplates a single molecule with twodiscreet monocationic groups, usually separated by a bridging group. Thedicationic liquid of the present disclosure can also be a mixture of oneor more dicationic liquid salts as defined herein.

The term “heterocyclyl” means a saturated (i.e., “heterocycloalkyl”),partially saturated (i.e., “heterocycloalkenyl”), or completelyunsaturated (i.e., “heteroaryl”) ring structure containing a total of 3to 14 ring atoms. At least one of the ring atoms is a heteroatom (i.e.,N, P, As, O, S and Si), with the remaining ring atoms beingindependently selected from the group consisting of carbon, oxygen,nitrogen, and sulfur. A heterocyclyl may be a single-ring (monocyclic)or polycyclic ring structure.

The term “heterocyclyl” encompasses protonated heterocyclyls such aspyridinium, pyridazinium, pyrimidinium, pyrazinium, imidazolium,pyrazolium, thiazolium, oxazolium and triazolium.

A heterocyclyl may be a single ring, which typically contains from 3 to7 ring atoms, more typically from 3 to 6 ring atoms, and even moretypically 5 to 6 ring atoms. Examples of single-ring heterocyclylsinclude furanyl, dihydrofuranyl, tetrahydrofuranyl, thiophenyl(thiofuranyl), dihydrothiophenyl, tetrahydrothiophenyl, pyrrolyl,pyrrolinyl, pyrrolidinyl, imidazolyl, imidazolinyl, imidazolidinyl,pyrazolyl, pyrazolinyl, pyrazolidinyl, triazolyl, tetrazolyl, oxazolyl,oxazolidinyl, isoxazolidinyl, isoxazolyl, thiazolyl, isothiazolyl,thiazolinyl, isothiazolinyl, thiazolidinyl, isothiazolidinyl,thiadiazolyl, oxadiazolyl (including 1,2,3-oxadiazolyl,1,2,4-oxadiazolyl, 1,2,5-oxadiazolyl (furazanyl) or 1,3,4-oxadiazolyl),oxatriazolyl (including 1,2,3,4-oxatriazolyl or 1,2,3,5-oxatriazolyl),dioxazolyl (including 1,2,3-dioxazolyl, 1,2,4-dioxazolyl,1,2,3-dioxazolyly or 1,3,4-dioxazolyl), oxathiazolyl, oxathiolyl,oxathiolanyl, pyranyl, dihydropyranyl, thiopyranyl,tetrahydrothiopyranyl, pyridinyl (azinyl), piperidinyl, diazinyl(including pyridazinyl (1,2-diazinyl), pyrimidinyl (1,3-diazinyl),pyrazinyl (1,4-diazinyl)), piperazinyl, triazinyl (including1,3,5-triazinyl, 1,2,4-triazinyl, and 1,2,3-triazinyl)), oxazinyl(including 1,2-oxazinyl, 1,3-oxazinyl, or 1,4-oxazinyl)), oxathiazinyl(including 1,2,3-oxathiazinyl, 1,2,4-oxathiazinyl, 1,2,5-oxathiazinyl,or 1,2,6-oxathiazinyl)), oxadiazinyl (including 1,2,3-oxadiazinyl,1,2,4-oxadiazinyl, or 1,3,5-oxadiazinyl)), morpholinyl, azepinyl,oxepinyl, thiepinyl, and diazepinyl.

A heterocyclyl may alternatively be polycyclic or contain more than onering. Examples of polycyclic heterocyclyls include bridged, fused, andspirocyclic heterocyclyls. In a spirocyclic heterocyclyl, one atom iscommon to two different rings. In a bridged heterocyclyl, the ringsshare at least two common non-adjacent atoms. In a fused-ringheterocyclyl, multiple rings may be fused together, such that two ringsshare one common bond. Examples of fused ring heterocyclyls containingtwo or three rings include indolizinyl, pyranopyrrolyl, 4H-quinolizinyl,purinyl, naphthyridinyl, pyridopyridinyl (includingpyrido[3,2-b]-pyridinyl or pyrido[3,4-b]-pyridinyl), and pteridinyl.Other examples of fused-ring heterocyclyls include benzofusedheterocyclyls, such as indolyl, isoindolyl (isobenzazolyl,pseudoisoindolyl), indoleninyl (pseudoindalyl), isoindazolyl(benzpyrazolyl), benzazinyl (including quinolinyl (1-benzazinyl) orisoquinolinyl (2-benzazinyl)), phthalazinyl, quinoxalinyl, quinazolinyl,benzodiazinyl (including cinnolinyl (1,2-benzodiazinyl) or quinazolinyl(1,3-benzodiazinyl)), benzopyranyl (including chromanyl orisochromanyl), benzoxazinyl (including 1,2,3-benzoxazinyl,1,2,4-benzoxazinyl, or 1,3,4-benzoxazinyl), and benzisoxazinyl(including 1,2-benzisoxazinyl or 1,4-benzisoxazinyl).

The term “heterocyclylalkyl” refers to the group —Z-heterocyclyl where Zis lower alkylene or substituted lower alkylene group.

The term “imidazolium” or “unsubstituted imidazolium” refers to apositively charged polyatomic ion with the chemical structure of

wherein the R group is H or an organic radical group.

The term “protonated tertiary amine” refers to a positively chargedpolyatomic ion with the chemical formula

wherein the R groups are organic radical groups. An “optionallysubstituted protonated tertiary amine” is a tertiary amine wherein theorganic radical group, R, is optionally substituted with other organicradical groups.

The term “phosphonium” refers to a positively charged polyatomic ionwith the chemical formula

wherein the R groups are individually H or an organic radical group. An“optionally substituted phosphonium” is a phosphonium wherein theorganic radical group, R, is optionally substituted with other organicradical groups.

The term “triionic salt” is used to describe a salt molecule, although,as the context suggests, it may be used synonymously with “triionicliquid” (“TIL”) and “triionic liquid salt” (“TILS”). A “triionic liquid”or “triionic liquid salt” in accordance with the present disclosure is aliquid comprised of a triionic salt. Thus, sufficient triionic saltmolecules are present such that they exist in liquid form at thetemperatures indicated herein. A TIL is either (1) a tricationic liquidor (2) a trianionic liquid. A “tricationic liquid salt” or “tricationicliquid”, as mentioned above, is either a salt molecule or a liquidcomprised of tricationic salt(s), wherein the tri cationic salt(s) isformed between a tricationic species and one or more counter-anions ofequal, greater than, or less than opposite charge. This contemplates asingle molecule with three discreet monocationic groups, usuallyseparated by bridging groups. The tricationic liquid of the presentdisclosure can also be a mixture of one or more tricationic liquid saltsas defined herein.

The chemical terms defined herein have the same meaning when they arecombined with another term(s). For example, the term “alkylamino” means“amino” substituted with “alkyl”, each group as defined above.

B. DICATIONIC LIQUID SALTS

In one embodiment, there is provided a dicationic liquid salt comprisinga dicationic species of Formula I:

and at least one counter-anion, wherein each R is one or moresubstituents independently selected from alkyl, alkoxy, carbocyclyl,carbocyclylalkyl, heterocyclyl, heterocyclylalkyl and hydroxyalkyl; mmeans a number of R substituents on an imidazolium ring and each m isindependently 0 (i.e., no substitution), 1, 2, 3 or 4; and s is 1, 2, 3,4, 5 or 6.

In a particular aspect, R is one or more independently selectedsubstituents such as methyl, ethyl, propyl, butyl, ethenyl, methoxy,ethoxy, propoxy, butoxy, phenyl, cyclohexane, benzyl, cyclohexanemethyl,hydroxymethyl, hydroxyethyl and hydroxypropyl; m is 0, 1 or 2,particularly 1 or 2; s is 1, 2 or 3, particularly 2 or 3. In someembodiments, m is 1, 2 or 3; and s is 1, 2 or 3.

In another particular aspect, each R is C₁-C₁₀-alkyl, hydroxyl,carbocyclylalkyl, heterocyclylalkyl or hydroxyalkyl; m is 1 or 2; and sis 2 or 3. In yet another particular aspect, R is methyl, ethyl, propyl,butyl, hydroxyalkyl or benzyl; m is 1 or 2, particularly 1; and s is 2or 3.

In a further embodiment, a dicationic liquid salt comprises a dicationicspecies corresponding in structure to Formula I(a):

and at least one counter-anion, wherein n is independently 1, 2, 3, 4,5, 6, 7, 8, 9 or 10; and s is 1, 2, 3, 4, 5 or 6. In a particularaspect, n is independently 1, 2 or 3; and s is 1, 2 or 3, particularly 2or 3.

In a particular embodiment, n is 1; s is 3; and the counter ion istriflate:

In a particular embodiment, n is 2 and in a further embodiment, n is 2,s is 3, and the counter ion is fluoride or triflate, and thus, thediionic species is:

In a further embodiment, a dicationic liquid salt comprises a dicationicspecies corresponding in structure to Formula I(b):

and at least one counter-anion, wherein s is 1, 2, 3, 4, 5 or 6,particularly 1, 2 or 3, and more particularly 2 or 3.

In a particular embodiment, s is 3 and the counter ion is triflate, andthe diionic species is:

In a further embodiment, a dicationic liquid salt comprises a dicationicspecies of Formula I(c):

and at least one counter-anion, wherein s is 1, 2, 3, 4, 5 or 6,particularly 1, 2 or 3, and more particularly 2 or 3.

In a particular embodiment, s is 3 and the counter ion is triflate, andthe diionic species is:

FIGS. 1 and 7 and Table 1 describe exemplary embodiments of additionaldicationic species.

In general, the counter-anions used to create the dicationic liquid saltmay be any suitable counter-anions. The salt forming counter-anions maybe monoionic such as, for example, Br⁻, or dianionic such as, forexample, succinic acid. The counter-anions need not be identical.Examples of suitable counter-anions include, without limitation, OH⁻,F⁻, Br⁻, Cl⁻, dicarboxylate, disulfonate, disulfate, triflate (TfO⁻),NTf₂ ⁻, PF₆ ⁻ and BF₄ ⁻. In a particular aspect, a counter-anion isselected from triflate, NTf₂ ⁻, haloalkylsulfonate and halocarboxylate.In another particular embodiment, a counter-anion is triflate, as shownbelow:

In one embodiment, the dicationic liquid salt has a solid/liquidtransformation temperature at about 100° C. or lower, will notsubstantially decompose and is substantially nonvolatile at atemperature below 200° C. and has a liquid range of about 200° C. orhigher. In another embodiment, the present disclosure comprises adicationic liquid salt having a temperature of solid/liquidtransformation temperature at 25° C. or lower, which will notsubstantially decompose and is substantially nonvolatile at atemperature below 300° C. or has a liquid range of about 300° C. orhigher.

In one embodiment, either the dicationic species is chiral, having atleast one stereogenic center. In such instances, the dicationic liquidsalts may be racemic (or in the case of diastereomers, each pair ofenantiomers is present in equal amounts) or they may be opticallyenhanced. “Optically enhanced” in the case of enantiomers means that oneenantiomer is present in an amount which is greater than the other. Inthe case of diastereomers, at least one pair of enantiomers is presentin a ratio of other than 1:1. Indeed, the dicationic liquid salts may be“substantially optically pure” in which one enantiomer or, if more thanone stereogenic center is present, at least one of the pairs ofenantiomers, is present in an amount of at least about 90% relative tothe other enantiomer. The diionic liquid salts of the disclosure mayalso be optically pure, i.e., at least about 98% of one enantiomerrelative to the other.

C. TRICATIONIC LIQUID SALTS

In some embodiments, there is provided a central group tricationicliquid salt comprising a trication of Formula II:Gc(A)₃  Formula IIwherein Gc is a central group and each A is independently a monoionicgroup; and at least one counter-anion, wherein each A may be the same ordifferent so long as they are all cations.

In some embodiments, A is chiral and therefore contains at least onestereogenic center. Non-limiting examples of A include carbocyclyl,heterocyclyl, quaternary ammonium, protonated tertiary amine,phosphonium or arsonium groups.

In some embodiments, each A is a monoionic group selected from the groupconsisting of alkylene, alkenylene, alkynylene,(—CH₂-carbocyclyl-CH₂—)_(v), and polysiloxyl; wherein alkylene,alkenylene, and alkynylene optionally contain one or more heteroatomsselected from the group consisting of O, N, S and Si; wherein themonoionic group is substituted with a cationic group selected from thegroup consisting of heterocyclyl, quaternary ammonium, protonatedtertiary amine and phosphonium; wherein the cationic group optionally issubstituted with one or more substituents independently selected fromthe group consisting of alkyl, cycloalkyl, phenyl, halo, alkoxy andhydroxyl; wherein the alkyl optionally is substituted with one or moresubstituents selected from the group consisting of hydroxy and phenyl;and v is selected from the group consisting of 1 to 20, inclusive.

In some embodiments, the A groups are identical.

In some embodiments, the monoionic A group selected from the groupconsisting of imidazolium, ammonium, phosphonium and pyridinium. In someembodiments, A is independently selected from the group consisting of:

wherein R₁, R₂, R₃ and R_(m) can be the same or different, and each ofR₁, R₂, R₃ and R_(m) is independently selected from alkyl, alkoxy,carbocyclyl, carbocyclylalkyl, heterocyclyl, heterocyclylalkyl andhydroxyalkyl. In a particular aspect, each of R₁, R₂, R₃ and R_(m) isindependently selected from methyl, ethyl, propyl, butyl, ethenyl,methoxy, ethoxy, propoxy, butoxy, phenyl, cyclohexane, benzyl,cyclohexanemethyl, hydroxymethyl, hydroxyethyl and hydroxypropyl.

Gc is a central group (also referred to as a center or central moiety)that may be substituted or unsubstituted, saturated or unsaturated,aliphatic, including straight or branched chains, cyclic or aromatic,and which may contain, in addition to, or even instead, of carbon atomsand hydrogen, N, P, As, O, S and Si atoms. The central group is not acharged ionic group. In some particular aspects, Gc is phenyl,cycloalkyl, Si, C, N or P; and A is as described above.

The central group (Gc in Formula II) or center interposed among theionic species can be of any length or any composition which affords apolyionic liquid salt of suitable properties. These include the groupsidentified as Gc above. There are certain factors that should beconsidered in selecting such a central moiety. First, the larger thepolyionic molecule in general, the greater the chance that the meltingpoint or temperature of solid/liquid transformation will be elevated.This may be less of a concern where the liquid range need not beextensive and/or where the temperature of solid/liquid transformationneed not be very low. If, however, as is often the case, one desires aliquid range of about 200° C. or higher and/or a solid/liquidtransformation temperature at 100° C. or lower, the size of the overallmolecule can become a larger and larger factor. On the other hand, alarger mass might be good for certain mass spectrometry applications.Second, in some embodiments, it is preferable that the central grouphave some flexibility. In such embodiments, a linear molecule, usuallysaturated, or a cyclic or polycyclic group of limited unsaturation canbe used as the central group. In some other embodiments, a more rigidpolyionic molecule may be desirable. In such embodiments, a high degreeof unsaturated groups, very rigid and/or stericly bulky groups, such asthose found in, for example, cholesterol, and polyunsaturated aliphaticgroups with extensive unsaturation, acryl groups, and cyclic groupsincluding multiple fused ring structures, can be used as the centergroup. In still another embodiment, the central group can be a singleatom such as C, Si, N and P.

The central group may be aliphatic, cyclic, or aromatic, or a mixturethereof. It may contain saturated or unsaturated carbon atoms or amixture of same with, for example, alkoxy groups (ethoxy, propoxy,isopropoxy, butoxy, and the like). It may also include or be madecompletely from alkoxy groups, glycerides, glycerols and glycols. Thecentral group may contain hetero-atoms such as O, N, S or Si andderivatives such as siloxanes, non-protonated tertiary amines and thelike. The central group may be made from one or more cyclic or aromaticgroups such as a cyclohexane, an immidazole, a benzene, a diphenol, atoluene, or a xylene group or from more complex ring-containing groupssuch as a bisphenol or a benzidine. These are merely representative andare not meant to be limiting. Generally, however, the central group willnot contain an ionically charged species, other than the polyanions orpolycations. And, it is possible to make mixtures of PILS each having,for example, the same cationic species, and each having the samecounterions, but differing in the central groups alone. Other variationsare also contemplated.

In some embodiments, this disclosure provides a polyionic liquid salt inwhich the central group is a linear central group having lengths rangingfrom a length equivalent to that of a saturated aliphatic carbon chainof between about 2 and about 40 carbon atoms (e.g., n=C₂-C₄₀ whencentral group is composed of carbon). Such a polyionic liquid salt istermed a linear-Gc-based polyionic liquid salt. More preferably, thelength should be approximately that resulting from a saturated aliphaticcarbon chain of about 3 to about 30 carbon atoms in length.

In some other embodiments, the disclosure provides a polyionic liquidsalt in which the central group is a cyclic central group having atleast a three member ring. Such a polyionic liquid salt is termed acyclic-Gc-based polyionic liquid salt. In embodiments involving a cycliccentral group, the number of carbons and/or any heteroatoms in thecentral group can be between 3 and about 40 (e.g., n=C₃-C₄₀ when centralgroup is composed of carbon). More preferably, the number of carbonsand/or any heteroatoms in the central group can be between 5 to about30. The cyclic central group can have, but are not limited to a 3, 4, 5,6 or 7-membered ring. The cyclic central group can also have a fusedmultiple ring.

The cyclic central group can be an alicyclic group containing one ormore all-carbon rings which may be either saturated or unsaturated,either substituted or unsubstituted. Exemplary alicyclic groups include,but are not limited to, cycloalkanes such as cyclopropane, cyclobutane,cyclohexane and cycloheptane, bicyclic alkanes such as norbornene andnorbornadiene, and polycyclic cycloalkane such as Decalin, Spiro groups,which have bicyclic connected through one carbon atom, and cycloalkenessuch as cyclobutene, cyclopropene and cyclohexene.

The cyclic central group can be an aromatic group containing one or moreall-carbon rings which may be either substituted or unsubstituted.Exemplary aromatic groups include, but are not limited to, benzene,naphthalene, anthracene, benzo[a]pyrene, benzo[ghi]pyrene, chrysene,coronene, fluoranthene, tetracene, pentacene, phenanthrene, pyrene andtriphenylene.

The cyclic central group can be a heterocyclic group that contains atomsin addition to carbon, such as sulfur, oxygen or nitrogen, as part ofthe ring. The heterocyclic groups can be either saturated orunsaturated, either substituted or unsubstituted, either aromatic ornon-aromatic, single or fused. The heterocyclic groups can have, forexample, 3, 4, 5, 6 or 7 membered rings.

The cyclic groups can also have fused multiple rings. Examples of fusedmultiple rings include, but are not limited to, benzocyclobutene,pentalene, benzofuran, isobenzofuran, indole, isoindole, benzothiophene,benzo[c]thiophene, benzimidazole, purine, indazole, benzoxazole,benzisoxazole, benzothiazole, naphthalene, anthracene, quinoline,isoquinoline, quinoxaline, acridine, quinazoline and cinnoline.

In embodiments in which the central group comprises a linear group and acyclic group, the monoionic groups can be distributed across the centralgroup in any manner. For example, some of the monoionic groups, A, areconjugated to the cyclic portion while other monoionic groups areconjugated to the linear portion of the central group.

Gc can be optionally substituted with one or more Rc sub stituentsindependently selected from the group consisting of a proton,substituted or unsubstituted, saturated or unsaturated, straight orbranched aliphatic chain (such as alkyl), cyclic group (such ascycloalkyl), aromatic group (such of phenyl or substituted phenyl),halo, alkoxy and hydroxyl.

In one embodiment, a polyionic liquid salt is a compound having thefollowing formula:

wherein each of R₁, R₂ and R₃ is independently methyl, ethyl, propyl,butyl, hydroxyalkyl or benzyl; and each Q is independently selected fromthe group consisting of alkylene, alkenylene, alkynylene,(—CH₂-carbocyclyl-CH₂—)_(n), and polysiloxyl; wherein alkylene,alkenylene, and alkynylene optionally contain one or more heteroatomsselected from the group consisting of O, N, S and Si; wherein Q isoptionally substituted with one or more substituents selected from thegroup consisting of alkyl, alkenyl, alkynyl, and alkoxy; and n isselected from the group consisting of 1 to 20, inclusive.

In a further embodiment, R₁, R₂ and R₃ are propyl, and the tricationicliquid salt comprises a tricationic species of Formula II(a):

and at least one counter-anion such as, for example,trifluoromethylsulfonate, 3TfO⁻. In a particular embodiment, thevariable Q is C₁₋₁₀-alkylene, particularly C₁₋₆-alkylene, and moreparticularly C₁₋₃-alkylene.

In a particular embodiment, Q is ethylene and the counter ion istriflate, and the triionic species is:

In some embodiments, a compound has a structure of Formula II(b):

wherein each t is independently selected from the group consisting of 1to 20, inclusive; and each A is independently as defined previously.

In one embodiment, A is phosphonium; and each of R₁, R₂ and R₃ isindependently methyl, ethyl, propyl, butyl, hydroxyalkyl or benzyl.

In a further embodiment, A is phosphonium, R₁, R₂ and R₃ are propyl, tis 5, and the anion is triflate, and the triionic species is:

In another embodiment, A is phosphonium, R₁, R₂ and R₃ are propyl, t is5, and the anion is NTF₂ ⁻ or F⁻, and the triionic species is:

In another embodiment, A is imidazolium. In a further embodiment, R₁ ismethyl or hydroxymethyl, t is 5, and the imidazolium has optionally oneor more methyl substitution, and the anion is F⁻. Non-limiting examplesof such triionic species include:

FIGS. 1 and 8 and Table 1 describe exemplary embodiments of additionaltricationic species.

In general, the counter-anions used to create the tricationic liquidsalt may be any suitable counter-anions. The salt forming counter-anionsmay be monoionic such as, for example only, Br⁻, or trianionic, such as,again for example only, succinic acid. The counter-anions need not beidentical. Examples of suitable counter-anions include, withoutlimitation, OH⁻, F⁻, Br⁻, Cl⁻, dicarboxylate, disulfonate, disulfate,triflate (TfO⁻), NTf₂ ⁻, PF₆ ⁻ and BF₄ ⁻ may be used. In a particularaspect, triflate, NTf₂ ⁻, haloalkylsulfonate and halocarboxylate isused.

In one embodiment, the tricationic liquid salt has a solid/liquidtransformation temperature at about 100° C. or lower, will notsubstantially decompose and is substantially nonvolatile at atemperature below 200° C. and has a liquid range of about 200° C. orhigher. In another embodiment, the present disclosure comprises atricationic liquid salt having a temperature of solid/liquidtransformation temperature at 25° C. or lower, which will notsubstantially decompose and is substantially nonvolatile at atemperature below 300° C. or has a liquid range of about 300° C. orhigher.

In one embodiment, either the tricationic species is chiral, having atleast one stereogenic center. In such instances, the tricationic liquidsalts may be racemic (or in the case of diastereomers, each pair ofenantiomers is present in equal amounts) or they may be opticallyenhanced. “Optically enhanced” in the case of enantiomers means that oneenantiomer is present in an amount which is greater than the other. Inthe case of diastereomers, at least one pair of enantiomers is presentin a ratio of other than 1:1. Indeed, the tricationic liquid salts maybe “substantially optically pure” in which one enantiomer or, if morethan one stereogenic center is present, at least one of the pairs ofenantiomers, is present in an amount of at least about 90% relative tothe other enantiomer. The triionic liquid salts of the disclosure mayalso be optically pure, i.e., at least about 98% of one enantiomerrelative to the other.

D. DEVICES

There is also provided a device useful in chemical separation, detectionor quantitation comprising: a solid support and at least one dicationicspecies of Formula I or tricationic species of Formula II which isadsorbed, absorbed or immobilized on the solid support. Any dicationicor tricationic species described herein, such as the dicationic and/ortricationic compounds shown in FIGS. 1, 7 and 8, may be suitable for usein chemical separation. Such a device is particularly useful forchemical separation, detection or quantitation of water from liquid, gasor solid samples.

In a particular aspect, the device comprises a syringe, a hollow needle,a plunger, and the solid support being attached to the syringe. In aparticular aspect, the device comprises an open tubular capillary columncoated with an ILS stationary phase.

Another embodiment is a device useful in chemical separation, detectionor quantitation, especially of water content, comprising: a solidsupport and one or more ILSs, such as for example species of FIG. 1,which is adsorbed, absorbed or immobilized on the solid support.

In a particular embodiment, the device for quantitating water in aliquid, gas or solid sample comprises a solid support and at least onepolyionic salt comprising a dicationic species of Formula I or atricationic species of Formula II and a counter-ion, wherein thepolyionic salt is adsorbed, absorbed or immobilized on the solidsupport:

wherein each R is independently selected from the group consisting ofalkyl, alkoxy, carbocyclyl, carbocyclylalkyl, heterocyclyl,heterocyclylalkyl and hydroxyalkyl; each m is independently 0, 1, 2, 3or 4; and s is 1, 2, 3, 4, 5 or 6, wherein Gc is phenyl, cycloalkyl, Si,C, N or P, wherein each A is independently selected from the groupconsisting of:

wherein each of R₁, R₂, R₃ and R_(m) is independently selected fromalkyl, alkoxy, carbocyclyl, carbocyclylalkyl, heterocyclyl,heterocyclylalkyl and hydroxyalkyl.

E. STATIONARY PHASES AND POLYMERIZATION

There is provided an immobilized dicationic liquid salt including one ormore dicationic liquid salts (with or without monoionic materials) asstationary phases, particularly in GC. These stationary phases arehighly selective, highly stable, and highly resistant to temperaturedegradation. These materials can be non-cross-linked (which often meansthat they are absorbed or adsorbed on a solid support or column), can be“partially” cross-linked or “more highly” cross-linked (which oftenmeans that they are “immobilized” on a solid support or column) and canbe composed of a mixture of dicationic liquid salts and dicationicmaterial and/or monocationic materials or can be made completely ofdicationic liquid salts in accordance with the present disclosure. Thepresence of unsaturated groups facilitates cross-linking and/orimmobilization.

In the case of non-cross-linked stationary phases, the polycationicliquid salts used may be saturated, unsaturated or a mixture of both. Itshould be understood, however, particularly if some amount ofunsaturated polycationic liquid salt(s) is used, and especially whereheat is used to fix the stationary phase, or the stationary phase isheated during use, as in gas chromatography, some degree ofcross-linking is possible.

“Partially” cross-linked stationary phases in accordance with thepresent disclosure permit production of a more stable, highly selectivestationary phase, allowing for high efficiency separations attemperatures up to approximately 280′C.

“More highly” cross-linked stationary phases in accordance with thepresent disclosure can provide superior efficiency and stability even attemperatures up to 350′C and higher. In “more highly cross-linked”stationary phases, the amount of polyionic species will surpass that ofany monoionic species. Preferably, more highly cross-linked stationaryphases will be composed substantially exclusively (90% or more) ofimmobilized polyionic liquid salts in accordance with the disclosure.

In a particular embodiment, the stationary phases are made from apolyionic species which is chiral and optically enhanced. Moreover,cross-linking and/or immobilization of the polyionic liquid salt in acolumn as a stationary phase, or to a solid support for SPE, SPME,TS-SPME, SPME/MALDI, ion chromatography, ion exchange chromatography,headspace analysis or other analytical or separation technique, does notappear to affect the selectivity of the stationary phase, therebypreserving its dual nature retention behavior.

And while stationary phases for GC and, in particular, capillary GC areone particular aspect of the present disclosure, the polyionic liquidsalts can be used as a stationary phase in other forms of chromatographyincluding, for example, LC and HPLC. Not only are the methods ofcreating stationary phases, solid supports and/or columns containingsame contemplated, the stationary phases, solid supports and columnsthemselves and the use of columns and solid supports containing thesestationary phases in chromatography, and other analytical or separationtechniques are contemplated as specific aspects of the disclosure.

A polyionic liquid salt can be coated on a capillary (or solid support)and optionally, subsequently polymerized and/or cross-linked by, forexample, two general methods. In the first method, the polyionic liquidsalt is coated via the static coating method at 40° C. using coatingsolution concentrations ranging from 0.15-0.45% (w/w) using solutions ofmethylene chloride, acetone, ethyl acetate, pentane, chloroform,methanol, or mixtures thereof. After coating of the polyionic liquidsalt is complete, the column is purged with helium and baked up to 100°C. The efficiency of naphthalene (other molecules such as n-hydrocarbonsor Grob Test Mixture can also be used for this purpose) is thenevaluated to examine the coating efficiency of the monomer ionic liquidstationary phase. If efficiency is deemed sufficient, the column is thenflushed with vapors of azo-tert-butane, a free radical initiator, atroom temperature. After flushing with the vapors, the column is thenfused at both ends and heated in an oven using a temperature gradient upto 200° C. for 5 hours. The column is gradually cooled and thenre-opened at both ends, and purged with helium gas. After purging withhelium gas overnight, the column is then heated and conditioned up to200° C. After conditioning, the column efficiency is then examined usingnaphthalene at 100° C. and the stationary phase coated layer examinedunder a microscope. Note that the cross-linking process can, and oftendoes, also cause immobilization. “Immobilized” in the context of thedisclosure means covalently or ionically bound to a support or toanother ionic liquid (including diionic liquid salts) or both. This isto be compared with ionic liquids which may be absorbed or adsorbed on asolid support. Solid supports in these particular instances are intendedto include columns (e.g., the walls of the columns).

It is not necessary, however, to cross-link these materials prior totheir use in GC. They may be adsorbed or absorbed in a column, or indeedon any solid support. However, at higher temperatures, their viscositymay decrease and they can, in some instances, flow and collect asdroplets which can change the characteristics of the column.Immobilization or partial cross-linking also reduces the vapor pressureof the stationary phase film which translates into lower column bleedthereby increasing the useful upper temperature limit of the phase andcolumn.

In another embodiment, there is provided a process which includes thefree radical reaction of ionic liquid monomers to provide a more durableand robust stationary phase, as well as the cross-linked and/orimmobilized stationary phases and the columns that include same. Bypartially cross-linking the ionic liquid stationary phase using a smallpercentage of free radical initiator, high efficiency capillary columnsare produced that are able to endure high temperatures with littlecolumn bleed. It was found that low to moderate temperature separations(30° C.-280° C.) can be carried out with high selectivity and efficiencyusing special partially cross-linked ionic liquid stationary phasemixtures. These stationary phases retain their “gelatinous,” “semiliquid,” amorphous state. For separations conducted at highertemperatures (300° C.-400° C.), more highly cross-linked/immobilizedstationary phases are well-suited to provide high selectivity andefficient separations with low column bleed. The effect of differentfunctionalized ionic liquid salt mixtures and initiator concentrationsis studied for these two types of stationary phases. The goal is tomaximize their separation efficiency, thermal stability, and columnlifetime, without sacrificing the unique selectivity of the stationaryphase.

The following materials can be used to prepare cross-linked stationaryphases comprising diionic liquid salts in accordance with the presentdisclosure: 1-vinylimidazole, 1-bromohexane, 1-bromononane,1-bromododecane, 1,9-dibromononane, 1,12-dibromododecane,1-bromo-6-chlorohexane, 1-methylimidazole,N-Lithiotrifluoromethanesulfonimide, AIBN, dichloromethane and ethylacetate.

It has been demonstrated previously that room temperature ionic liquidsact as broadly applicable, superb gas chromatographic stationary phasesin that they exhibit a dual nature retention behavior. Consequently,ionic liquid stationary phases have been shown to separate, with highefficiency, both polar and nonpolar molecules on a single column. Byproducing stationary phases that are either partially or highlycross-linked, it is of interest to ensure that the solvationthermodynamics and solvation interactions inherent to ionic liquids arestill retained by their immobilized analogues.

In another embodiment a mixed stationary phase (MSP) is provided. TheMSP comprises at least one dicationic liquid salt of the disclosure andstationary phase material such as, but not limited to, polysiloxanes,polyethylene glycols (“PEGs”), methylpolysiloxanes, phenyl substitutedmethylpolysiloxane, nitrile substituted methylpolysiloxane and carbowax.Such MSPs can be used as a stationary phase in chromatography such asGC, LC and HPLC as well as in SPE and SPME. The MSPs can benon-cross-linked (e.g., absorbed or adsorbed on a solid support orcolumn), can be “partially” cross-linked or “more highly” cross-linked(i.e., immobilized on a solid support or column). The dicationic liquidsalt may also be cross-linked or otherwise reacted with the stationaryphase material or merely mixed therewith.

Appropriate combinations of the polycationic liquid salt and thestationary phase material for producing a MSP is based on the particularapplication as are the proportions of the dicationic liquid salt and thestationary phase material in the MSP.

In a particular embodiment, the ratio of the polycationic liquid saltand the stationary phase material in the MSP is from about 1:9 (i.e.,about 10% of polycationic liquid salt and 90% of stationary phasematerial) to about 9:1 (i.e., about 90% of polycationic liquid salt andabout 10% of stationary phase material), about 1:3 (i.e., about 25% ofpolycationic liquid salt and about 75% of stationary phase material) toabout 3:1 (i.e., about 75% of polycationic liquid salt and about 25% ofstationary phase material), about 1:2 (i.e., about 33% of polycationicliquid salt and about 67% of stationary phase material) to about 2:1(i.e., about 67% of polycationic liquid salt and about 33% of stationaryphase material), or about 1:1 (i.e., about 50% of polycationic liquidsalt and about 50% of stationary phase material) (w/w). Chromatographyemploying MSP may perform better, e.g., having higher selectivity, thanchromatography employing polycationic liquid salt or the stationaryphase alone. As an example, an MSP comprising a simple mixture of about67% (dibutyl imidazolium)₂(CH₂)₉ and about 33% of methylpolysiloxanewith about 5% phenyl substitution was prepared and used to coat acolumn. This MSP was shown to exhibit better separation of an essentialoil. A cross-linked version of the MSP can also be used.

In addition, the disclosure also provides methods of preparing MSPs,solid supports and/or columns containing same, the MSPs, solid supports,syringes, tubes, pipettes tips, needles, vials, and columns themselves,and the use of columns and solid supports containing such MSPs inchromatography and other analytical or separation techniques such asthose described elsewhere herein.

F. METHODS OF QUANTITATING, SEPARATING AND/OR DETECTING WATER

Analyzing water in organic solvents is generally damaging fortraditional commercial columns, leading to appreciable degradation andcontinuously changing chromatograms. It is found that a stationary phaseusing polyionic liquid salts is not substantially altered or degraded bywater. Therefore, this disclosure provides improved methods forquantitating, separating and/or detecting water in a liquid, gas orsolid sample comprising one or more chemicals, the method comprising:providing the liquid, gas or solid sample comprising water and the oneor more chemicals; and exposing said liquid, gas or solid sample to atleast one solid support including at least one dicationic and/ortricationic species, such as a species of Formula I or II, which isadsorbed, absorbed or immobilized on the solid support.

Water contents in products, such as pharmaceutical or food products, canhave influence on their physicochemical properties. In particular cases,water contents have to be strictly controlled to comply withindustry/government regulations and guidance, such as regulations of theFood and Drug Administration (FDA). Thus, a method for quantitating,separating and/or detecting water of this disclosure has broadapplication in many industries. In various embodiments, the method ofthis disclosure is performed in chemical, pharmaceutical and/or foodindustry for various purposes. Non-limiting examples of suchapplications include detection/quantitation of water in solvents,determination of water purity, and detection/quantitation of water infood products or alcoholic beverages.

In an embodiment, the method is used to quantitate water in a liquidsample such as organic solvents. Non-limiting examples of such organicsolvents include acetic acid, acetone, acetonitrile, anisole, benzene,1-butanol, 2-butanol, 2-butanone, t-butyl alcohol, carbon tetrachloride,chlorobenzene, 1-chlorobutane, chloroform, 2-chloropropane, cyclohexane,cyclohexanone, 1,2-dichlorobenzene, 1,2-dichloroethane,1,3-dichloropropane, diethyl ether, di(ethylene glycol) ethyl ether,1,2-dimethoxy-ethane (glyme, DME), dimethyl-formamide (DMF), dimethylsulfoxide (DMSO), dioxane, ethanol, ethyl acetate, ethylene glycol,heptane, hexane, methanol, methyl t-butyl ether (MTBE), methylenechloride, N-methyl-2-pyrrolidinone (NMP), nitrobenzene, nitromethane,nitroethane, octane, 1-octanol, pentane, petroleum ether (ligroine),1-propanol, 2-propanol, pyridine, tetrahydrofuran (THF), toluene,triethyl amine, o-xylene, m-xylene, and p-xylene.

In a particular embodiment, a method for quantitating, separating and/ordetecting water comprises use of a capillary gas chromatographic methodemploying a solid support including at least one dicationic and/ortricationic species of Formula I or II. A method for quantitating,separating and/or detecting water may comprise direct detection using athermal conductivity detector (TCD).

In an embodiment, a method of this disclosure further comprisesproducing a chromatogram showing one or more peaks of moleculescontained in the sample. A water and solvent chromatogram produced bythe method has sufficient separation space for an appropriate, baselineseparated internal standard. The chromatogram shows a considerabledifference in the retention of water and all organic solvents. Invarious embodiments, water peak of the chromatogram shows goodefficiency and symmetry.

Any dicationic and/or tricationic species described herein, such as thespecies shown in FIGS. 1, 7 and 8, may be used for quantitating,separating and/or detecting water in a sample. In various aspects, thedicationic and/or tricationic species is selected from species ofFormulae I(a), I(b), I(c), II(a) and II(b). In a particular aspect, thedicationic and/or tricationic species is selected from species ofFIG. 1. In a more particular aspect, the method uses a solid supportcontaining a polyionic liquid salts comprising a species selected fromthe group consisting of:

“Retaining” in this context does not mean permanently. Separation canoccur in a syringe device by removal of the device from the sample orejection of the second chemical. In the case of a chromatography column,the first chemical (or water) will be absorbed or adsorbed at adifferent rate than the second chemical, which may be at a greater rateor a lower rate, thus resulting in separation. Both are moved throughthe column by a mobile phase, which can be a liquid or a gas (e.g.,helium) and their interaction with the stationary phase (the ionicliquid materials on the solid support) at different rates causesseparation. This is what is meant by “retention” in the context ofchromatography. However, in certain types of chromatography, it is alsopossible that the first chemical is bound to the stationary phase whilethe second chemical is not and is carried through the column by themobile phase until it elutes. The first chemical can be eluted orremoved separately and this is also embraced by the word “retained.”

In a particular embodiment, there is provided a liquid, gas or solidchromatography method for detecting or quantitating a component in aliquid, gas or solid sample, comprising: applying a sample to acapillary column having a gas chromatography stationary phase comprisinga dicationic species of Formula I or a tricationic species of Formula IIand a counter-ion, wherein Formulae I and II are as defined above;separating a component from the sample; and quantitating the componentby using a detector. In various embodiments, the component to bequantitated by the method is water impurity or organic solvent impurityin the liquid sample.

EXAMPLES

The following examples are merely illustrative, and do not limit thisdisclosure in any way.

Example 1

An ionic liquid (IL) based capillary gas chromatographic method with TCDfor the direct determination of water content in liquid samples wasexamined. The unique nature of Ils, including; high thermal stabilities,variable polarities and exceptional stability to water and oxygen makethem excellent choices as stationary phases for this methodology. Asshown below, open tubular capillary columns, coated with specific ILstationary phases (developed for water analysis) can tremendouslyenhance the sensitivity, applicability and reliability of thistechnique. Furthermore, analysis times can be decreased to 6 minutes oreven less than 3 minutes in many cases, and samples with virtually anyconcentration of water can be analyzed. The efficacy of this approach isdemonstrated with 50 different solvent samples.

1.1. Apparatus

The analysis was performed using an Agilent Technologies 6890N gaschromatograph (Agilent technologies Inc., Wilmington, Del.), equippedwith a 7683B series autoinjector, TCD and Chemstation plus software(Rev. B.01.03). An Agilent technologies 10 μl syringe (5181-1267), wasused with the autosampler, while a Hamilton 10 μl syringe was used forall manual injections. The other experimental parameters are given inTables 1 and 2 below. The fused silica capillary columns were coatedwith IL stationary phases synthesized as previously reported. Thecolumns were 30 m long, 0.25 mm internal diameter (I.D.) and 0.2 μm filmthickness. KF analysis was performed using Aquastar V1B volumetrictitrator (EM Science, a division of EM industries, Inc., Chemy Hill,N.J.).

TABLE 1 GC/TCD parameter for the analysis of water. Carrier gas HeliumCarrier gas flow rate (ml/min)  1.0 Inlet temperature (° C.) 250Detector temperature (° C.) 250 Injection volume (μl) Vary (0.2-5) Oventemperature (° C.) Vary (40-120) Analysis mode Splitless

TABLE 2 Experimental parameters for detection of water in 50 solvents.HMIM-PEG TTP DMIM-PEG Oven Oven Oven Temp Inj. Vol. Temp Inj. Vol. TempInj. Vol. Sample (° C.) IS (μl) (° C.) IS (μl) (° C.) IS (μl) Aceticacid 120 A 0.2 120 A 2.0 100 C 0.2 Acetone 70 C 2.0 70 C 1.0 70 C 1.0Acetonitrile 50 A 0.2 70 A 0.2 70 A 2.0 Anisole X X X 120 A 1.0 70 C 2.0Benzene 50 C 5.0 70 C 5.0 70 C 5.0 1-Butanol 50 C 0.2 70 C 1.0 X X X2-Butanol 50 C 0.2 X X X 70 A 0.2 2-Butanone 70 C 2.0 70 C 1.0 70 C 0.2t-Butyl alcohol 40 C 0.2 70 A 0.2 70 C 0.2 Carbon tetrachloride 70 C 5.070 C 5.0 70 C 5.0 Chlorobenzene 50 A 1.0 70 C 1.0 70 A 1.01-Chlorobutane 70 C 3.0 70 C 5.0 70 C 5.0 Chloroform 50 C 1.0 70 A 5.070 C 5.0 2-Chloropropane 50 C 1.0 70 C 2.0 70 C 2.0 Cyclohexane 70 C 5.070 C 5.0 70 C 5.0 Cyclohexanone 70 A 1.0 120 A 2.0 100 C 0.21,2-Dichlorobenzene X X X 100 A 2.0 X X X 1,2-Dichloroethane 50 C 2.0 70A 2.0 70 C 0.2 1,3-Dichloropropane 50 A 0.2 X X X 50 A 2.0 Diethyl ether70 C 2.0 70 C 2.0 70 C 2.0 Di (ethylene glycol) 120 A 1.0 120 A 0.5 100C 0.2 ethyl ether 1,2-Dimethoxy-ethane 70 C 2.0 70 C 2.0 70 C 0.2(glyme, DME) Dimethyl- 100 A 1.0 120 A 0.2 100 C 0.2 formamide (DMF)Dimethyl 120 A 1.0 120 A 0.2 100 C 0.2 sulfoxide (DMSO) Dioxane 50 A 0.270 A 1.0 50 A 0.2 Ethanol 50 A 0.2 70 A 0.2 50 A 0.2 Ethyl acetate 50 C1.0 70 C 2.0 70 C 5.0 Ethylene glycol 120 A 0.2 120 A 0.2 100 C 0.2Heptane 70 C 5.0 70 C 5.0 70 C 5.0 Hexane 70 C 5.0 70 C 5.0 70 C 5.0Methanol 50 A 0.2 70 A 0.2 70 A 0.2 Methyl t-butyl 70 C 2.0 70 C 1.0 70C 0.2 ether (MTBE) Methylene chloride 70 C 2.0 70 C 2.0 70 C 2.0N-methyl-2- 120 A 0.2 120 A 0.5 100 A 0.2 pyrrolidinone (NMP)Nitrobenzene 120 A 2.0 120 A 2.0 100 A 1.0 Nitromethane 50 A 0.2 X X X XX X Nitroethane 50 A 0.2 X X X X X X Octane 50 C 5.0 70 C 5.0 70 C 5.01-Octanol 70 C 1.0 120 A 2.0 100 C 5.0 Pentane 70 C 5.0 70 C 5.0 70 C5.0 Petroleum ether (ligroine) 70 C 5.0 70 C 3.0 70 C 5.0 1-Propanol 50A 0.2 X X X 70 A 0.2 2-Propanol 50 A 0.2 70 A 2.0 70 C 0.2 Pyridine X XX 70 A 2.0 X X X Tetrahydrofuran (THF) 70 C 2.0 70 C 1.0 70 C 0.2Toluene 40 C 1.0 50 A 2.0 70 C 5.0 Triethyl amine 50 C 2.0 70 C 2.0 70 C2.0 o-Xylene 50 A 1.0 X X X 50 A 3.0 m-Xylene 50 A 1.0 X X X 50 A 5.0p-Xylene 50 A 1.0 X X X 50 A 5.0 IS is the abbreviation for “internalstandard” which was either A = acetone or C = acetonitrile.

1.2. Materials

The water reference material: 8509, moisture in methanol (MeOH, 97±13ppm water) was obtained from National Institute of Standards andTechnology (NIST, Gaithersburg, Md.). The 4 Å molecular sieves, hydranalwater standard 1.0, tetrahydrofuran (THF) and both the internalstandards (1S), acetone and acetonitrile, were purchased fromSigma-Aldrich (St. Louis, Mo.). Aquastar combititrant 2 and Aquastarmethanol were purchased from EMD chemicals (Gibbstowm, N.J.). The highpurity water was obtained by filtering the deionized water withMillipore, synergy 185. The testing solvents were from, Sigma-Aldrich,Mallinckrodt, EMD, Fisher, Omni solvent, and Acros organics.

1.3. Sample Preparation

The accurate quantification of water was achieved using one of twointernal standards (ISs), either acetone or acetonitrile. Two differentISs were available in case one co-eluted with the analyte solvent underthe conditions of the experiment. Internal standards were dried to <10mg/kg by storing over 30% w/v 3 A molecular sieves for seven days priorto use. A typical sample preparation involved drying a 2 ml autosamplervial overnight at 130° C. followed by the addition of approximately 1 mlof solvent. The mass of the solvent was recorded using an analyticalbalance. 5.0 mg of internal standard was added prior to analysis.

1.4. Methods

For initial screening, the columns were conditioned at 120° C. for 2hours and high purity water was injected, 0.1 μl, using 100:1 splitratio at the desired temperature. The sample of interest was injected inthe splitless mode (0.2 μl to 5 μl), in order to examine the separationbetween water and the bulk solvent. This preliminary experiment helpedin determining which IS should be used.

Water quantitation was achieved by integration of the internal standardpeak and the water peak. The concentration of internal standard in mg/kgwas multiplied by the ratio of water peak to internal standard peak andthe result was divided by the response factor. The resulting numberrepresents the concentration of water in the sample in mg/kg. Eachsolvent was prepared in triplicate and each individual sample wasinjected in triplicate for a total of n=9 individual integrations foreach solvent analyzed.

1.5. Detection Limit and Quantitation Limit

The detection limit (LOD) and the quantitation limit (LOQ) werecalculated according to the guidelines of the US Food and DrugAdministration (FDA), using the following equations:

${LOD} = \frac{3.3\sigma}{S}$ ${LOQ} = \frac{10\sigma}{S}$wherein σ is the standard deviation of the response, and S is the slopeof the calibration plot.

The σ is normally obtained from the standard deviation of the blanksample. Since it is impossible to obtain a sample without water, thefirst point of the calibration plot, where there is no added water, isused as the blank sample and its standard deviation was used as σ. Theslope was obtained from the regression analysis of the plot; peak arearatio of water and I.S. vs amount of water.

1.6. Results

FIG. 1 shows the structures of the three ionic liquids that were used asstationary phases in this example, i.e., (1)bis-3-hydroxyalkylimidazolium-PEG triflate (HMIM-PEG TfO⁻); (2) trigonaltripropylphosphonium triflate (TTP TfO⁻); and (3)bis-2,3-dimethylimidazolium-PEG triflate (DMIM-PEG TfO⁻). Generally, ILstationary phases containing trifluoromethylsulfonate (TfO⁻) anionsresulted in more symmetric water peak shapes than those of thatcontained PF₆ ⁻, BF₄ ⁻ or bis[(trifluoromethyl)sulfonyl]imide (NTf₂ ⁻),with the same cation. The triflate counterion is important in deliveringsharp, symmetrical water peak shapes. In addition to the IL-based GCcolumns, a commercially available polyethylene glycol (PEG) column alsowas evaluated for comparison purposes.

FIG. 2 shows the gas chromatography separations of small amounts ofwater impurities from two of the organic solvents that were analyzed.Chromatograms A and C are isothermal separations. Chromatogram B is forthe same sample as in A. However a temperature gradient was used todecrease the analysis time and further “sharpen” the water peak. Thisenhanced the sensitivity and precision of the method. Conditions forchromatogram A were: 1 μl injection; 50° C.; analysis time: 9 minutes;Internal Standard: acetone (0.4%). Conditions for chromatogram B were: 1μl injection; 50° C. (hold 2 minutes), ramp 10 dpm to 80° C.; analysistime: 6 minutes, Internal Standard: acetone (0.4%). Conditions forchromatogram C were: 0.2 μl injection; 110° C., analysis time: 8minutes, Internal Standard: acetone (0.2%). The water peak can be elutedeither before or after the large organic solvent peak depending on therelative elution order of the two on the ionic liquid-based stationaryphases. In most cases the “separation window” between the water andsolvent peaks is sufficiently large as shown in FIG. 2(A) that a thermalgradient can be used to further narrow the peak width of water andreduce analysis times as shown in FIG. 2(B).

A comparison of the separation of water from methylene chloride on an ILcolumn versus a commercial PEG type column is shown in FIG. 3 where theconditions were injection 1 μl, temperature 80° C. The ionic liquidbased columns (A), (B) and (C) produced better peak shapes andselectivity even though the separation conditions were optimized for thePEG column and not the IL one. In all cases (for all solvent samples),the IL-based separations were substantially better in terms ofselectivity and efficiency.

Table 3 compares the amount of water measured in ten solvents and a NISTmethanol standard using four different capillary GC methods and the KarlFischer titration (KFT). The samples were chosen so that the KFTanalysis could be done without the use of special reagents (e.g., as areneeded to quantify water in aldehydes and ketones). Also most of thesesamples could be analyzed on the commercial PEG column.

TABLE 3 Comparison of the ionic liquid GC results with the best resultsfrom the Karl Fischer Titration (KFT) and the use of a commercial PEG GCcolumn. HMIM-PEG TTP DMIM-PEG Commercial KF^(a) Sample H₂O/ppm RSD^(b)H₂O/ppm RSD^(b) H₂O/ppm RSD^(b) H₂O/ppm RSD^(b) H₂O/ppm RSD^(b)Tetrahydrofuran 110 6.0 108 5.8 117 8.1 77 12.0 179 5.2Dimethylformamide 594 4.0 606 4.9 614 6.2 X^(c) X^(c) 678 4.3 t-Butylalcohol 2130 1.9 2010 6.2 1950 4.0 1868 8.3 2006 6.4 Dimethyl 773 2.9800 4.4 820 5.0 740 11.3 796 4.6 sulfoxide Ethanol 890 2.0 880 3.8 8802.0 670 11.2 809 4.0 Ethyl acetate 370 2.8 365 3.9 371 1.0 327 6.7 5095.6 Methanol 209 7.1 198 4.6 203 5.0 173 21.0 241 6.0 Methylene 48 8.252 6.3 47 7.3 78 5.5 117 3.3 chloride 1-Propanol 308 4.0 X^(c) X^(c) 2853.2 X^(c) X^(c) 365 7.1 2-Propanol 180 3.9 171 2.4 162 3.0 179 14.0 2324.0 NIST MeOH 104 4.0 99 3.8 114 5.8 47 8.0 158 8.6 Std. (97 ± 13 ppm)^(a)Five grams of sample were used for all KFT except for those with thelowest water concentrations. Ten grams of sample were used for themethanol and tetrahydrofuran and fifteen grams for methylene chloride.Twelve grams of sample were used for the NIST methanol standard.^(b)Minimum of three determinations were done. ^(c)No adequate valuecould be obtained with this column because of excess overlap betweensolvent and internal standard or between the solvent and the waterpeaks.

As can be seen from the data above, the ionic liquid based columnsusually produced the most precise and accurate results (as indicatedfrom the residual standard deviations (RSDs) and NIST standard,respectively). There are a few things to be noted about the data. First,no more than one microliter of sample was used for any of the capillaryGC determinations. Conversely, the KF titrations utilized between 5 and15 grams of sample depending on the water content of the solvents(larger samples were required for samples containing the least water) asshown in Table 3. The limits of detection (LOD) and limits ofquantitation for the IL columns were better than those found for thecommercial PEG column even when analyzing samples and using conditionsthat are necessary for favorable separations on the PEG column as shownin Table 3. The detection limit of coulometric KFT is 10 μg, and itrequires at least 5 g of sample. The IL based GC method required only0.2 μl of sample to obtain a much lower detection limit (about 2.0 ng orabout 5,000× greater sensitivity) as shown in Table 4.

TABLE 4 Limits of detection (LOD) and limits of quantitation (QL) ofwater in the evaluated columns. HMIM-PEG TTP DMIM-PEG Solvent LOD/ngQL/ng LOD/ng QL/ng LOD/ng QL/ng MeOH/A^(a) 3.6 10.9 4.0 12.0 4.1 12.4THF/C^(b) 2.1 6.3 5.6 16.9 3.0 9.0 ^(a)“A” indicates that acetone wasused as the internal standard. ^(b)“C” indicates that acetonitrile wasused as the internal standard.

Table 5 lists the water content of 50 different solvents as determinedwith the three IL columns evaluated in this study. FIG. 5 indicates thenumber of these solvents that could be successfully analyzed on eachcolumn. Only two could only be done on each of the HMIM-PEG and TTPcolumns. The HMIM-PEG was the most broadly useful stationary phase as itproduced adequate separations of water from 47 out of the 50 testedsolvents. To be considered a successful separation, the water (analyte)peak had to be separated from both the solvent and at least one of theinternal standards (i.e., acetone or acetonitrile). FIG. 5 shows thatall three IL columns could be used to quantify water in 38 out of the 50solvents. The HMIM-PEG-TFO overall was the most successful as it couldbe used to quantify water in 47 of the solvent samples, including twosamples that were not amenable to separation on the other testedcolumns.

TABLE 5 Detection of water in 50 solvents. HMIM-PEG TTP DMIM-PEG WaterRSD Water RSD Water RSD Sample (ppm) % (ppm) % (ppm) % Acetic acid 4201.0 410 5.9 440 5.0 Acetone 2380 3.8 2380 6.1 2520 0.3 Acetonitrile 1033.0 98 6.9 103 2.7 Anisole X X 990 2.6 990 3.5 Benzene 18 2.4 17 8.4 219.5 1-Butanol 1190 3.6 1150 5.8 X X 2-Butanol 3530 2.6 X X 3380 2.32-Butanone 730 3.7 760 1.2 710 5.8 t-Butyl alcohol 2130 1.9 2010 6.21950 4.0 Carbon tetrachloride 36 3.7 38 4.4 36 5.7 Chlorobenzene 38 9.642 8.9 39 3.1 1-Chlorobutane 27 5.5 23 5.0 28 3.7 Chloroform 155 2.3 1535.1 162 6.3 2-Chloropropane 120 4.0 113 5.3 125 4.2 Cyclohexane 18 9.721 7   20 3.5 Cyclohexanone 8630 0.9 8450 5.4 8710 1.01,2-Dichlorobenzene X X 12 6.0 X X 1,2-Dichloroethane 160 6.9 150 13.7 140 2.4 1,3-Dichloropropane 114 4.9 X X 102 1.5 Diethyl ether 400 7.6420 1.6 390 6.4 Di(ethylene glycol) 950 4.3 970 9.5 930 2.1 ethyl ether1,2-Dimethoxy- 7500 1.5 7600 1.4 7300 0.6 ethane (glyme, DME) Dimethyl-594 4.0 606 4.9 614 6.2 formamide Dimethyl sulfoxide 773 2.9 800 4.4 8205.0 Dioxane 3800 4.0 3700 3.5 3900 2.3 Ethanol 890 2.0 880 3.8 880 2.2Ethyl acetate 370 2.8 365 3.9 370 1.4 Ethylene glycol 170000 3.5 1690005.3 179000 3.2 Heptane 18 6.3 17 8.7 16 8.7 Hexane 14 5.3 17 9.5 16 9.0Methanol 209 7.1 198 4.6 203 5.0 Methyl t-butyl 1900 1.1 1800 6.1 19006.6 ether Methylene chloride 48 8.2 52 6.3 47 7.3 N-methyl-2- 18700 5.718500 4.8 19000 2.1 pyrrolidinone Nitrobenzene 119 2.5 109 8.5 117 3.9Nitromethane 920 5.0 X X X X Nitroethane 770 3.2 X X X X Octane 13 8.017 10.0  14 5.1 1-Octanol 190 4.6 210 7.0 190 5.6 Pentane 16 3.4 18 9.615 4.8 Petroleum ether 16 3.9 19 6.1 17 4.6 (ligroine) 1-Propanol 3084.0 X X 285 3.2 2-Propanol 180 3.9 171 2.4 162 3.0 Pyridine X X 910 4.6X X Tetrahydrofuran 110 6.0 108 5.8 117 8.1 Toluene 31 4.2 29 5.0 32 4.6Triethyl amine 56 0.3 57 0.2 57 6.7 o-Xylene 74 7.7 X X 76 4.9 m-Xylene22 7.9 X X 24 0.6 p-Xylene 23 9.2 X X 26 0.2 The symbol “X” indicatesthat the water peak was not adequately separated from the solvent peak.All other experimental conditions are given in Tables 1 and 2.

The TTP TfO⁻ column was used to quantify water in 42 solvents, includingpyridine and 1,2-dichlorobenzene which were not possible using the othertwo columns that were investigated. The DMIM-PEG TfO₂ ⁻ column oftengave the best, separation window between the water peak and solventpeaks, compared to the other columns. Hence all the separations that arepossible on this column can be done at even higher temperatures thatthose used in this disclosure (Tables 3 and 4) or using temperaturegradients (FIG. 2(B)) if desired. In most cases this means that manyanalyses times can be less than 3 minutes.

FIG. 6 illustrates the use of capillary columns containing ionic liquid(IL) stationary phases in the measurement of trace amounts of organicsolvents in water, wherein conditions for chromatogram A were DMIM-PEG,40° C., 0.2 ml injection, thermal conductivity detector (all solvents:100 mg/kg); and conditions for chromatogram B were DMIM-PEG, 40° C., 0.2ml injection, flame ionization detector (all solvents: 5 mg/kg). In FIG.6(A), TCD was used in order to show the elution of the water peakrelative to trace organic solvents. In FIG. 6(B), even lowerconcentrations of the organic contaminants were seen when using flameionization detection (FID). Water cannot be seen with this detector. Theinjection of water samples is not recommended on ordinary commercialcolumns that are not based on ionic liquids. Virtually all traditionalcommercial columns showed appreciable degradation and continuouslychanging chromatograms when analyzing water samples. Analyzing water fororganic solvents tends to be much more damaging for these columns thananalyzing organic solvents for trace amounts of water. For example,three successive commercial PEG columns had to be used for this studywhile the separations and conditions of all IL columns used remainedunchanged throughout the study (>1,600 injections).

A rapid, facile IL-based GC method has been developed for thequantification of water in extremely diverse solvent samples. Limits ofdetection using this technique are superior when compared to KFT.Furthermore, the IL-GC methodology requires less sample and is free fromother complications associated with KFT. The IL GC method can be usedregardless of the chemical nature of the solvent and produces noadditional waste products. When compared to other GC methods usingcommercially available PEG columns, the IL based columns possessedsuperior selectivity for water in all solvents tested. Further, theyshow no degradation or chromatographic changes with time. Typicalanalysis times ranged from <3 min to 7 min.

What is claimed is:
 1. A method for detecting or quantitating water in aliquid sample comprising: applying a liquid sample to a capillary columnhaving a gas chromatography stationary phase comprising at least onedicationic species of Formula I:

and a counter-ion, wherein each R is independently selected from thegroup consisting of alkyl, alkoxy, carbocyclyl, carbocyclylalkyl,heterocyclyl, heterocyclylalkyl and hydroxyalkyl; each m isindependently 0, 1, 2, 3 or 4; and s is 1, 2, 3, 4, 5 or 6; andseparating water from the liquid sample to detect or quantitate water inthe liquid sample.
 2. The method of claim 1, wherein the detecting orquantitating water comprises direct detection using a thermalconductivity detector.
 3. The method of claim 1, further comprisingproducing a chromatogram showing one or more peaks of a moleculecontained in the liquid sample.
 4. The method of claim 1, wherein thegas chromatography stationary phase is not substantially altered ordegraded by a liquid sample containing water.
 5. The method of claim 1,wherein the capillary column comprises a solid support and a dicationicspecies adsorbed, absorbed or immobilized on the solid support.
 6. Themethod of claim 1, wherein the method has a lower detection limit ofabout 10⁶ ng/L water.
 7. The method of claim 1, wherein the counter-ionis selected from the group consisting of F⁻, NTf₂ ⁻ and trifilate. 8.The method of claim 1, wherein the at least one dicationic species isselected from the group consisting of:

wherein each n is independently 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10; andeach s is independently 1, 2, 3, 4, 5 or
 6. 9. The method of claim 1,wherein the at least one dicationic species and the counter-ion areselected from the group consisting of:

wherein the counter-ion is selected from F⁻, NTf₂ ⁻ and trifilate.